The dog, or canine, vaccination series usually begins when puppies are six to eight weeks old. The series consists of three or four visits, the last of which takes place when the puppy is about four months old. Once the puppy has completed the "puppy shots," it should return to the veterinarian yearly for booster vaccinations to maintain a protective antibody level. Veterinatians commonly vaccinate and test dogs for:

CANINE DISTEMPER -- a highly contagious disease caused by a virus; it is spread among dogs by contact through the mouth or nose. The virus can attack all parts of the body, including the nervous system. It is usually fatal.

LEPTOSPIROSIS -- a bacterial infection spread by contact with infected, urine-contaminated water. It is marked by a high fever and a yellow color of the gums and can cause permanent kidney damage. If untreated, it can be fatal for your pet and this disease can be contracted by humans.

KENNEL COUGH -- an infection caused by the bordetella bacterium and the parainfluenza virus. The disease, also known as infectious tracheo-bronchitis, is characterized by a continual honking bronchial cough. It is transmitted when an infected dog coughs and infective particles are inhaled by other dogs. As the name implies, it can be easily transmitted in a kennel where many dogs are present.

RABIES -- transmitted by the rabies virus, which enters the body through a break in the skin -- often a bite from an infected animal. It is almost always fatal. Rabies is contagious to all land mammals, including humans. It is a very serious disease and should never be taken lightly. That's why there's so much emphasis on rabies vaccinations. It's important for owners to get their pets immunized and keep their vaccinations current. In fact, in most states the law requires that dogs and cats be current on their rabies vaccinations.

HEARTWORMS -- transmitted from dog to dog by mosquitoes. A mosquito bites an infected dog, drawing out some of the dog's blood. The mosquito then bites an uninfected dog and injects the saliva, contaminated with microfilariae, into the uninfected animal. For this reason, areas of the country with a lot of mosquitoes (warm climates and areas near water) experience worse problems with heartworms than areas with fewer mosquitoes. Heartworms are detected with filter and occult blood tests. X-rays of the chest can also be helpful in diagnosing this parasite. A dog must test negative for heartworms with a blood test before beginning preventative medication. Any dog taken off the medication must test negative again before beginning the medication again. The treatment for heartworms is serious and can be stressful to the dog. Usually the dog must be hospitalized for several days and medication is administered to kill the adult heartworms. The dog then goes home, with instructions for restricted activity and complete rest. This is to keep the dog's blood pressure down, which prevents the dead worms from forming a clot and blocking a major blood vessel in the lungs. In the second part of the treatment, the dog is given an oral medication to kill the microfilarie. The dog's blood is checked to make certain that all the microfilariae are gone. Once the dog is negative for microfilariae, it can then begin taking heartworm prevention medication.

FECAL -- tests for intestinal parasites living inside your pet's body such as tapeworms, roundworms, hookworms, coccidia and whipworms. Some of these parasites can also infect humans so great care should be taken when cleaning an area used by a pet infected by worms.